Apparatus for forging taper pins



Dec. 13, 1949 F. s. FLICK APPARATUS FOR FORGING PAPER PINS 2Sheets-Sheet 1 Filed July 28, 1943 Patented Dec. 13, 1949 APPARATUS FORFORGING TAPER PINS I Francis S. Flick, Chicago, Ill., assignor toWilliam J. Reedy and Francis S. Flick, a partnership doing business asMiller Motor Company Application July 28, 1943, Serial No. 496,515

2 Claims.

This invention relates to an improved apparatus for forging taper pins,and more particularly to apparatus that can be operated, if desired, bya punch press.

Heretoiore, taper pins have been made on screw machines which are moreexpensive than punch presses and cannot be as readily obtained as punchpresses. By using the present method, the cost of manufacturing taperpins is greatly lessened, steel is saved, and the pins are more accurateas to size than pins as commonly manufactured commercially. By thepresent invention, taper pins are being made with a tolerance of plus.0013.

Another object of the invention is to make taper pins by a processsimilar to cold heading and avoid excessive flash metal around the endof the Another object of the invention is to provide an improved methodof lubricating the cylindrical blank of steel which is to be made into apin, so that the finished taper pin may be readily removed from the dieand there will be no serious voids or channels on the face of thefinished pin because of the lubricant.

Other objects of the invention are to provide an improved knock-out pinand apparatus for supplying compressed air and operating the knock-outpin automatically by mechanism secured to the punch head.

The invention is illustrated in the preferred embodiment of theaccompanying drawings, in which- Figure 1 is a fragmentary sectionalview showing the improved apparatus secured to the bolster plate and ramof a conventional punch press; Figure 2, a fragmentary sectional viewshowing a cylindrical blank placed in the die and ready for the formingoperation; Figure 3, a view similar to Figure 2 showing a second step inthe op eration wherein the knock-out pin is retracted to formingposition and the punch is advancing towards engagement with thematerial; Figure 4, another view similar to Figures 2 and 3 but showingthe punch in its lowermost position having just formed a taper pin; andFigure 5, a fragmentary plan sectional view, taken as indicated at line5 of Figure 4.

In the embodiment illustrated, the die is secured to a bolster plate 6of a punch press having a ram 1 to which is secured a head 8 by means oftie rods 9. A cylinder 10 is secured to the lower side of the bolsterplate by means of bolts and contains a piston I l which is secured tothe head 8 by means of a piston rod 32. Air inlet ports Ella areprovided in the cylinder wall. The piston rod is adjustable and has ahead l3 adapted to actuate the knock-out pin member M at the end of thetop stroke of the piston l l.

The die 55 is preferably made of high carbon tool steel and has an uppercylindrical portion l6 and a lower cylindrical portion H which areconnected by a tapered opening H3 in which the taper pin is formed. Thedie is securely bolted to the bolster plate by means of bolts and thebolster plate may be provided with leader pins l9 to be engaged byleader pin bushings 23 secured to the ram so as to guide the punch 2|accurately into the opening IS. The punch 2| may be secured to the ramby an upper die shoe 22, in the well known manner, and preferably thelower end of the punch has a hollow point 2 la to give the end of thetaper pin the final rounded form. Preferably, the punch is made of toughsteel such as chrome vanadium steel.

The upper end of the cylinder Ill is counterbored to provide a shoulder23 upon which the knock-out pin support plate 24 may rest during theforming operation. The upper portion of the knock-out pin support plateis recessed to receive the enlarged head portion 25 of the knock-out pinM. This head prevents the knock-out pin from advancing too far into thedie 15 when it is ejecting a taper pin from the die. The knock-out pinI4 preferably has a hollow point 26 which forms a closure for the dieduring a pin forming operation. It will be noted that the sides of theknockout pin l 4 are flattened, as indicated at 21, to permit aircompressed by the packing 28 on the piston and passed through openings29 in the knockout pin support plate, to pass into the die and finallyeject the taper pin after it has been loosened by the knock-out pin.

In order to obtain the best results, cylindrical blanks 30, which areusually of cold drawn steel, should be properly treated so that thefinished pins will be smooth and can easily be extracted from the die.It is common for taper pins to have one-fourth of an inch of taper perfoot of length. If lubricants are used, they must be carefully applied.Ordinary lubricating oil is unsatisfactory as it is very dilficult toavoid oil marks because the oil is practically incompressible and iscompletely confined within the die during the forming operation. Dieselengine oil and kerosene are used in making relatively short pins but forlong pins the most satisfactory lubricant is white lead. The blanksshould be wiped with white lead and then rolled between two fabric facesso as to remove the excess material and apply a very thin even coat.After the pins have been so treated with white lead, they should be usedand compressed rather promptly. If exposed to the air for a period oftwo or three hours, satisfactory results are not obtained.

The operation will be readily understood by reference to Figures 2, 3,and 4. The operator places the blank 30 in the die l and trips thepress. As the plunger descends to the position shown in Figure 3, theknock-out pin [4 travels down with its supporting plate until its topedge is even with the small end of the taper opening in the die. Whenthe plunger completes its downward stroke to the position shown inFigure 4, the blank is compressed between the knock-out pin and the endof the punch and completely fills the taper portion of the die andaccordingly takes its shape. It is important that the punch travel downthrough the enlarged cylindrical portion l6. of the die, as thisprevents breakage of the punch which thereby does not have anopportunity to be deflected olT its true center. As the punch 21 closelyfits the opening I6, there is very little flash of metal around thepunch and this small amount of waste metal may be readily ground oii ofthe finished pin. On the return stroke of the ram, the piston H andpacking 28 in its upward travel compresses air and near the top of itsstroke strikes the knock-out pin support plate and drives the knock-outpin into the die loosening the finished pin in the die. At this momentthe compressed air is admitted into the die beneath the taper pin and itis blown out of the die so that the next blank may be inserted.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom for some modifications will be obvious to those skilled in theart.

I claim:

1. Apparatus for forming taper pins, which comprises: an open ended diehaving at one. end a cylindrical portion to receive a. punch and at theother end a smaller cylindrical portion to receive a knock-out pin, saidcylindrical portions being joined bya tapered opening of. the length andsize of the taper pin to be formed a punch to enter the largercylindrical portion; a knockout pin to enter the smaller cylindricalportion of the die; means for holding the knock-out pin with its innerend even with the end. of the tapered portion of the die; a pumpcylinder secured to the die member; a piston in said cylinder secured tothe punch so that when the punch is retracted the pistonis advanced tocompressair in. said pump cylinder and then to abut and movesaidknock-out pin to loosen the formed taper pin, and means renderedoperative by the movement of said knock-out pin to admit the compressedair into said die to blast the formed taper pin therefrom.

2. Apparatus for forming taper pins, comprising, an open ended diehaving a cavity to receive the blank of the taper pin to be formed, apunch to enter one end of the opening in the die, a closely fittingknock-out pin to enter the other end of the opening in the die to form aclosure for the die, a cylinder substantially fixed with relation tosaid die, a piston in said cylinder and connected to move simultaneouslywith said punch, packing on said piston and slidably contacting theinner walls of said cylinder, a knockout pin support member havinglimited movement in the end of said cylinder adjacent one end of saiddie, said piston being out of contact with said supporting member untiljust before removal of the taper pin after it has been formed, aperturesin saidsupport member, said knock-out pin having an air passageway thatis normally closed prior to the piston striking the support member,whereby when a taper pin has been formed in the opening in the die andthe punch is retracted the piston will move toward the knock-out pinsupport member during recession. of the punch whereby when the pistonstrikes the supportmember the knock-out pin will loosen the formed taperpin in the die opening after which air compressed by the movement of thepiston will passthrongh the support-member and the knockout pin to ejectthe formed taper pin from the; die.

FRANCIS S. FLICK.

REFERENCES CITED The following references are of record in the file ofthis patent:

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